/Engine/Source/Runtime/HeadMountedDisplay/Public/IXRTrackingSystem.h
Get the current pose for a device. This method must be callable both on the render thread and the game thread. For devices that don't support positional tracking, OutPosition will be at the base position.
true if the pose is valid or not.
bool GetCurrentPose ( int32 DeviceId, FQuat & OutOrientation, FVector & OutPosition )